The following paragraphs are provided by way of background to the present disclosure. They are not however an admission that anything discussed therein is prior art or part of the knowledge of persons skilled in the art.
The biochemical pathways of living organisms are commonly classified as being either part of primary metabolism or part of secondary metabolism. Pathways that are part of a living cell's primary metabolism are involved in catabolism for energy production or in anabolism for building block production for the cell. Secondary metabolites, on the other hand, are produced by living cells without having any obvious anabolic or catabolic function. It has however long been recognized that many secondary metabolites are useful in many respects, including for example as therapeutic agents or natural deterrents.
The secondary metabolite (R)-Reticuline is produced by opium poppy (Papaver somniferum) and other members of the plant families Papaveraceae, Lauraceae, Annonaceae, Euphorbiaceae and Moraceae, and may be used as a source material for producing the pharmaceutically active compounds including morphine and codeine.
It is known that (R)-Reticuline in planta is produced from (S)-Reticuline. However it is not clear which genes and polypeptides are involved in catalyzing the conversion reaction(s).
Currently (R)-Reticuline may be harvested from natural sources, such as opium poppy. Alternatively (R)-Reticuline may be prepared synthetically. The existing manufacturing methods for (R)-Reticuline however suffer from low yields of (R)-Reticuline and/or are expensive. No methods exist to biosynthetically make (R)-Reticuline from (S)-reticuline. There exists therefore in the art a need for improved methods for the synthesis of (R)-Reticuline.